If you write JavaScript, you have probably used higher-order functions and not even noticed. If you have ever replaced a for loop with an array method, you’ve used higher-order functions.

Beyond the usual quick tips, let's look at both the business case and the technical side of keeping React bundles lean.

The JavaScript will then trigger any events or variables specified within it, the Document Object Model (DOM) will be updated, and, finally, the JavaScript will be rendered in the browser.

Understanding functions is important if you want to learn how to code. The same applies to current programmers who tend to copy their code quite often to use in a different section of their work.

The latest JavaScript specification standardizes a well-balanced and thoughtful set of features, including the built-in global Iterator, new Set methods, improvements to regular expressions, and more.